Thishas gone far enough. Not only is it creating practically imaginable for Guitar Hero and Rock Band, but it's apparently encouraging all manner of offshoots as well, real or virtual.
This "Quadruple-Neck Guitar" may not owe its origins to the current craze, but the trend probably didn't hurt the demand for it on eBay. We just have one question: What human play this thing? Dvice says it requires "proficiency in the intricacies of playing a bluegrass band full of real instruments," not to mention extraordinary manual dexterity to negotiate four necks.
Perhaps it's not for four-limbed individuals at all, but the latest example of another trend we've noticed--music gear.